Piston ring



Sept. 27, 1938. H. MORGAN PISTON RING Filed April 24, 1936' INVENTOR.HARFORD L. MORGAN Patented Sept. 27, 1938 v UNITED STATES" PATENT oFncsrrs'rou mo Hal-ford L. Morgan, San Francisco, Calif.

Application April 24, 1938, Serial No. 76,179 7 Claims. (01. zoo-4s) Thepresent invention relates to improvements in piston rings and itsprincipal object is to provide a piston ring that is particularlyv welladapted to serve the purpose of maintaining compression, has an easygliding fit with thewall of the cylinder and long wearing qualitiea.

More particularly it is proposed to provide a split piston ring with aninner spring for expanding the ring, the latter being preferablytensioned so as to normally close at the split and to cause the springto become the sole or main expanding factor in the assembly.

It is further proposed to use a split expansion spring of the serpentineor polygonal type and to arrange the ring in such a manner that the endsof the spring are prevented from accidentally projecting through thesplit of the ring and from scraping the cylinder wall.

It is further proposed, in a modified form, to

construct the ring of two split sections, one lying on top of the other,with the splits in non-registering relation, but with anchoring meansfor the spring arranged in registering relation.

It is further proposed to provide the piston ring, whether made in oneor two sections, with an inner groove for receiving the projectingportions of the serpentine or polygonal spring and to step the sidewalls of the groove so as to allow of free play of the spring within thegroove.

Further objects and advantages of my invention will appear as thespecification proceeds.

The prefered forms of my invention are illustrated in the accompanyingdrawing in which Figure 1 shows, in vertical section and in fragmentaryview, the relative arrangement of my piston ring and the piston and thecylinder wall,

Figure 2 a top plan view of one form of piston ring made in accordancewith my invention the ring being shown as being under compression,

Figure 3 a sectional view taken along line 3-4 of Figure 2,

Figure 4 a sectional view taken along line 4-4 of Figure 2,

Figure 5 a plan view of a modified form of my piston ring comprising twosections, a portion of the upper section being removed to show the lowersection and the ring being shown as being under compression, v

Figure 6 an inside view of the removed portion 60 of the upper section,

Figure '7 a sectional view taken along line 1-1 of Figure 5, and

Figure 8 a sectional view through the piston ring taken along line H ofFigure 5.

56 While I have shown only the preferred forms of my invention I wish tohave it understood that various changes or modifications may be madewithin the scope of the claims hereto attached without departing fromthe spirit of the invention. I

Referring to the drawing in detail it will be seen that Figure 1 showsthe conventional arrangement of the piston i having slight clearancerelative to the cylinder wall 2 and being provided with an annulargroove 3 for accommodati0 ing the piston ring 4. The latter which isillustrated as one form of my invention in Figures 2, 3 and 4, is of thesolid type, that is, made in one piece and is split as at 5.

The ring is made of elastic material and its 15 tension is preferablysuch that it is normally closed at the split, without leaving a gap. Thering is formed with a central groove 6 in the inner face thereof, thegroove being rectangular, in cross-section and the side walls of thegroove being stepped away from the center line of the groove as shown'at'l to provide greater clearance for the spring 8 accommodated in thegroove The spring is preferably polygonal or serpentine in form and itsouter corners 9 are received l5 in the groove, the width of the springcorresponding substantially to the width of the bottom of the groove sothat the extreme corners of the spring have a sliding fit therein whilethe stepped side walls allow greater clearance adjacent the 30 comers.The spring is split and is of such length that when properly positionedin the groove, the

free ends iii of the spring leave a gap and are disposed on oppositeends of stops ll formed in the-groove on opposite sides of the split'sothat ii any considerable lengthwise or rotary movement of the spring isprevented. The stops are formed by making the ring of solid rectangularcrosssection as shown in Figure 4. The spring has a natural tendency toopen the ring and to expand 40 the same against the cylinder wall.'

The bottom face of the piston ringis preferably formed with a slantingrecess l2 to provide a sharp edge for scraping any oil that mightattempt to pass the ring on the downward stroke 45 of the piston.

A modified and preferred form of the invention is shown in Figures 5-8in which the ring is made of two sections l3 and It, the formeroverlying the latter. The two sections are split as shown at 50 i5 andi6 and the two'splits are arranged in nonregistering relation,preferably diametrically opposite one another, as shown in Figure 5. Thesections are formed with annular recesses I1 and it which cooperate informing an annular groove ll I9 corresponding to the groove 6 of thesolid piston ring. The side walls of this groove are also stopped asshown at 20.

This groove is also formed with stops for limiting spring movement, thestops in the lower section being disposed on opposite sides of the split16 as shown at 2| and a registering stop 22 being formed in the uppersection diametrically opposite its split l5, each stop being made tocompletely fill the groove so that at the stop each section isrectangular in cross-section or end-view as shown in Figure '7.

The spring 23 is substantially the same as the spring 8 previouslydescribed and its free ends 24 are limited in their movement by thestops 2| and 22 respectively.

In this form the ring sections l3 and H are also made of elasticmaterial and are tensloned so as to normally close at their splits l andI6, while the spring tends to expand the ring against the cylinder wall.

This form of my ring has the advantage that due to the non-registry ofthe splits in the two sections no gap is formed when the ring isexpanded. It is also more sensitive and responsive to the spring actionsince each section is thinner and more flexible than the solid ring ofthe first form.

I claim:

1. A piston ring comprising two split ringsections arranged one on topof the other with the splits in non-registering relation, the sectionshaving annular recesses cooperating in forming an inner annular groovein the piston ring and having registering stops blocking a limitedportion of the groove and a split polygonal spring seated in the grooveand having its ends confronting opposite sides of the stops.

2. A piston ring comprising two split ring sections arranged one on topof the other with the splits in diametrically opposite relation, thesections having annular recesses cooperating in forming an inner annulargroove in the piston ring and having registering stops at one of thesplits for blocking a limited portion of the groove and a splitpolygonal spring seated in the groove and having its ends confrontingopposite sides of the stops.

3. A piston ring comprising two split ring sections arranged one on topof ti o'her with the splits in non-registering relation, the sectionshaving annular recesses cooperating in forming an inner annular groovein the piston ring and having registering stops blocking a limitedportion of the groove and a split expansion spring seated in the grooveand having its ends confronting opposite sides of the stops.

4. A piston ring comprising two split ring sections arranged one on topof the other with the splits in non-registering relation, the sectionshaving annular recesses cooperating in forming an inner annular groovein the piston ring and having registering stops blocking a limitedportion of the groove and a split expansion spring seated in the grooveand having its ends confronting opposite sides of the stops, the ringsections being tensloned to normally close at the splits so as to throwthe burden of expanding the ring entirely on the spring.

5. A piston ring comprising two split ring sections arranged one on topof the other with the splits in non-registering relation, the sectionshaving annular recesses cooperating in forming an inner annular groovein the piston ring and having registering stops blocking a limitedportion of the groove and a split expansion spring seated in the grooveand having its ends confronting opposite sides 01' the stops, the sidewalls of the groove being stepped back from the center-line of thegroove to facilitate ,free play of the spring in the groove.

6. In combination, a split piston ring having an annular groove in theinner surface thereof and a polygonal spring having its corners seatedwithin the groove and being tensloned for expanding the ring, the widthof the spring being substantially equal to that of the groove and theside walls of the groove being stepped back from the spring intermediatetheir height to facilitate free play of the spring within the groove.

'7. In combination, a split piston ring having an inner annular grooveand stops in the groove on opposite sides of the split and a splitpolygonal expansion spring having its comers seated in the groove andits ends disposed on opposite sides of the stops, the splits in the ringand in the spring being made to register to co-relate expansive play ofthe spring with responsive flexing of the ring and the side walls of thegroove being stepped back intermediate their height to clear the springfor free play immediately adjacent the corners of the spring.

HARFORD L. MORGAN.

